This invention relates to a method and apparatus for measuring and recording the temperature of an electrically conductive molten mass which is heated by electrodes immersed in the mass, particularly molten glass masses in glass melting furnaces and feeders, feeder heads and passages associated with such furnaces.
There is known a method for determining the temperature of molten glass masses by measuring the electrical conductivity of the molten glass mass; constant low voltage currents flow through the glass mass and the power required to maintain such voltage is used to calculate the temperature of the glass. However, there are drawbacks to this method. For one, auxiliary measuring electrodes must be brought into, and kept in contact with the molten glass mass. Furthermore, because of heating currents created by the heating electrodes, a constant low voltage current cannot be maintained, and the power cannot be measured easily or not at all.
Also, it is known to measure temperature by using thermocouples immersed in the molten glass mass. This has disadvantages in that replacement of broken thermocouples is difficult or impossible, and especially that measurement can only be made at a point directly adjacent a wall.
The present invention avoids these disadvantages and, in particular, makes it not only possible to measure or detect the temperature at separate points or measuring paths within a molten glass mass, but also to produce a precise pattern of the temperature profile or distribution, i.e. of the isotherms, within the molten glass mass.
The invention can be carried out without the use of auxiliary electrodes or thermocouples, is fast in operation and, particularly, provides information with respect to the temperature of individual measuring paths and the temperature distribution within the entire furnace.
The present invention also makes it possible to control the operation of a glass melting furnace by employing the temperatures measured in accordance with the invention.